Axial motion magnetically actuated switch

ABSTRACT

An axial motion switch which consists of a magnetic material armature attached to an end cap of a sealed vessel by means of a spring, flexible contact wire, or the like. The other end of the sealed vessel is provided with a magnetic, internally extended end cap which forms a pair of contacts with the free end of the armature. The two end caps are electrically insulated from each other by using a vessel of insulating material, such as glass or a metal vessel suitably insulated from the end caps. When the vessel is placed in a magnetic field of correct orientation, the armature is attracted axially by mutual magnetic pole induction to the internally extending end cap and the contact therebetween causes a low electrical resistance path to exist between the end caps of the switch device.

United States Patent 1191 Remington 1451 May 28, 1974 AXIAL MOTION MAGNETICA LLY ACTUATED SWITCH 5 8/1970 Scheidig 335/153 Primary Eraminer-Roy N. Envall. Jr.

[57] ABSTRACT An axial motion switch which consists of a magnetic material armature attached to an end cap of a sealed vessel by means of a spring, flexible contact wire, or the like. The other end of the sealed vessel is provided with a magnetic. internally extended end cap which forms a pair of contacts with the free end of the armature. The two end caps are electrically insulated from each other by using a vessel of insulating material.

such as glass or a metal vessel suitably insulated from the end caps. When the vessel is placed in a magnetic field vofcorrect orientation. the armature is attracted axially by mutual magnetic pole induction to the internally extending end cap and the contact thcrebetween causes a low electrical resistance path to exist between the end caps of the switch device.

1 Claim, 3 Drawing Figures 42 44 o f0 40 Q AXIAL MOTION MAGNETICALLY ACTUATEI) SWITCH BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a circuit closing device and more particularly to a circuit closing device in which the circuit closing elements themselves are of magnetic material enclosed in a hermetically sealed vessel so that when placed in a magnetic field of proper orientation the contacts are subject to induced magnetic forces of opposite polarity and wherein at least one of said circuit closing elements is axially actuthe glass tube. Although this type of switch is particularly useful for controlling electrical circuits, it is relatively expensive to manufacture in that generally the reed type switch must be manufactured by hand or, if by automatic machines, on a one at a time basis. In addition, the physical configuration and resulting close tolerances of the reed switch make the unit too expensive for many applications.

SUMMARY OF THE INVENTION lt is, therefore, an object of the present invention to provide a circuit closing device of the above type which can be fabricated or manufactured at reduced cost while maintaining the effectiveness and durability of the switch as well as reliability in operation. It is a futher object of the present invention to provide a low cost circuit closing device with hermetically sealed contacts whereinat least one of said contacts is magnetically actuated in an axial motion to make contact and close the circuit. Toward the fulfillment of these objects, the circuit closing device of the present invention comprises a switch structure that eliminates the complicated mechanical and magnetic structures of the prior art with a structure comprising a simple pair of magnetic contacts'which perform both the magnetic and electrical functions necessary to an electromagnetic circuitclosing device. The utilization of magnetic material for the contacts eliminates-the utilization of magnetic armatures so that the contacts are directly actuated by the magnetic field.

BRIEF DESCRIPTION OF THE DRAWINGS Reference is now made to the accompanying drawings for a better understanding of the nature and objects of the present invention. The drawing illustrates the best mode presently contemplated for carrying out the objects of the inv'entionand are not to be construed as restrictions or limitations on its scope.

IN THE DRAWINGS FIG. 1 is a sectional view of an axial motion switch in accordance with a preferred embodiment of the invention;

' FIG. 2 is a sectional view of another example of an axial travel switch which is normally closed,

FIG. 3 is a sectional view of a further clarification of the form of the invention.

DESCRlPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, is a glass vessel in which nonmagnetic end caps 12 and 14 have been sealed at opposite ends. To the end cap 12 is secured a spring or flexible contact wire 16 which supports an armature 18 at its free end, non-magnetic end cap 14 is provided with an internally extending flange 20 in which is supported a pole 22 of magnetic material. Armature 18 is provided with suitable noble metal in contact area 24 as is pole 22 at its contact surface 26. The envelope 10 may contain any suitable inert gas or any other appropriate non-corrosive gas.

The armature l8 and the pole 22 are appropriately mounted within the envelope so that they may close an electric circuit with the contact of surfaces 24'and 26. An energizing coil 28 connected to a suitable source of current is provided surrounding the envelope so when appropriately energized electro-magnetic lines of force act on the armature 18 and pole 22 to have them attract to each other and contact at 24 and 26 to thereby close an electric circuit between the end caps 12 and '14.-

In brief, the axial motion switch 10 when exposed to a magnetic field generated by the energizing coil 28 subjects the armature l8 and pole 22 to induced magnetic forces of opposite polarityand the armature l8 overcomes the retractile force of the spring 16 and moves axially to make contact with the pole 22. When the magnetic field is removed, the spring 16 returns to its original position and the continuity from the end cap 12 and the end cap 14 is open. In the preferred embodiment, the coil 28 is energized with an appropriate amount of dc. current to cause the armature 18 to overcome the retractile force of the spring 16; if desired, the energizing coil may be replaced by a bar or toroidal magnets which would serve a similar purpose.

FIG. 2 shows a switch device 29 with an envelope 30 having an opened end 32 provided with a glass header 34 suitably mounted therein to provide an hermetic seal between the glass header'and the envelope 30. A pole 35 is attached or fixed to a base 36 on which is secured a coil spring 38. An armature 40 is mounted on the free end of the coil spring so that the armature is axially spaced from the pole 35 to provide a predetermined contact gap therebetween. Fixed to the armature 40 is a bridging contact 42 which is insulated from the armature by a suitable insulation spacer 44, a pair of connectors 46 and 48 are mounted in the glass header 34 so that their respective end portions 50 and 52 are in contact with the bridging contact 42. The ends of the connectors are provided with a suitable plating of nickel, welded tungston, or silver cadmium oxide as required by the particular application of the switch device 29.

An energizing coil 54 is provided so that when the coil is energized with a suitable dc. current the armature 40 and the pole 35 are subjected to induced magnetic forces of opposite polarity and the armature overcomes the retractile force of the spring 38 to come in contact withthe pole 35. In this manner, the bridging contact 42 attached to the armature 40 no longer contacts the connector ends 50 and 52 so that the circuit between the connectors 46 and 48 is opened. When the switch device 29 is no longer magnetically actuated, the armature 40 will become subject to the spring force and move away from the pole 35 and the bridging contact 42 closes the circuit between the connectors 46 and 48.

F [6.3 shows an envelope 56 provided with end caps 58 and 60 which are fabricated of non-magnetic material. The end caps 58 and 60 are provided with flange portions integral therewith on which are mounted springs 62 and 64, respectively. An armature device 66 is mounted on the spring 62 secure to the end cap 58 and another armature device 68 is mounted on spring 64 attached or mounted on end cap 60. The armatures 66 and 68 are provided with contact ends 70 and 72, respectively. An energizing coil 74 is suitably mounted adjacent the envelope 56 so that when energized, the armatures 66 and 68 are subject to induced magnetic forces of opposite polarity and the armatures overcome the retractile force of their respective springs 66 and 68 and move toward each other to make contact. Where larger contact gaps or immunity from shock and vibration are required in an axial motion switch, the double armature device of FIG. 3 is ideally suited so that under the forces of shock or vibration, the armature 66 and While the present invention has been described in preferred embodiments, it will be obvious to those skilled in the art that various modifications can be made therein within the scope of the invention and it is intended that the appended claims cover all such modifications.

What is claimed is:

l. A circuit closing device operable by magnetic forces, comprising a metal envelope having an opened any contact problems.

end, a glass header mounted within said opened end to provide a hermetic seal between said glass header and said envelope, a pole mounted within and secured to the base of said envelope, a coil spring secured at one end to said pole, an armature mounted on the free end of said coil spring and axially spaced from said pole, an insulation spacer mounted on one end of said armature opposite the end axially spaced from said pole, a bridging contact mounted on said insulation spacer, a pair of connectors mounted in said glass header and having connector ends within said envelope in contact with said bridging contact, an energizing coil provided surrounding said envelope and connected to a source of current so when energized said armature overcomes the retractile force of said spring to contact said pole and axially displace said bridging contact from said connector ends to open the circuit between said pair of COHDCCIOI'S. 

1. A circuit closing device operable by magnetic forces, comprising a metal envelope having an opened end, a glass header mounted within said opened end to provide a hermetic seal between said glass header and said envelope, a pole mounted within and secured to the base of said envelope, a coil spring secured at one end to said pole, an armature mounted on the free end of said coil spring and axially spaced from said pole, an insulation spacer mounted on one end of said armature opposite the end axially spaced from said pole, a bridging contact mounted on said insulation spacer, a pair of connectors mounted in said glass header and having connector ends within said envelope in contact with said bridging contact, an energizing coil provided surrounding said envelope and connected to a source of current so when energized said armature overcomes the retractile force of said spring to contact said pole and axially displace said bridging contact from said connector ends to open the circuit between said pair of connectors. 